/**
* @file   hello.cpp
* @author WHH <whhern@gitee.com>
* @date   Wed Sep 22 18:41:30 2021
*
* @brief  A demo program for learning.
*/

#include<iostream>
/**
 * main function.
 *
 * @param argc number of shell parameters.
 * @param argv strings for all parameters.
 *
 * return system signals.
 */

int main(int argc, char *agrv[])
{
  /// Just a demo.
  std::cout<<"Hello World!"<<std::endl;
  return 0;
};
